Enhancement of AlxGa1-xN nanowire array photocathode with heterojunction Al composition assisted by external electric field

Abstract

The UV detection technology in the solar-blind band urgently needs to make a substantial breakthrough, and the performance of the AlxGa1-xN detector is also continuously improved. Therefore, we propose a heterojunction AlxGa1-xN nanowire array photocathode assisted by external electric field. In order to solve the problem of insufficient electron collection capability of the nanowire array photocathode, the built-in electric field introduced by the heterojunction structure can promote the drift and diffusion of the carriers inside the nanowire to the top surface. The participation of external electric field-assisted methods also can make the photoelectrons escaping from the side of the nanowire change the flight trajectory to increase electron collection. Using the above concept to build a photo-emission and electron-collection model of AlxGa1-xN nanowire array photocathode with heterojunction Al composition, it is concluded that the GaN-Al0.27Ga0.73N heterojunction nanowires have the best quantum efficiency. In addition, when the external electric field is 2.5V/μm, the large-spacing heterojunction Al-component nanowire array with an incident angle of 30 ° can obtain an overall electron collection ratio of nearly 100%. This study can provide some theoretical support for the performance improvement of vacuum-type solar blind UV detectors based on the AlxGa1-xN nanowire array photocathode with heterojunction Al composition. The field-assisted heterojunction AlxGa1-xN nanowire array cathode are expected to be verified by the experimental results in the future.